<?php
$n=$_GET['number'];
$u=$_GET['user'];
$x=$_GET['id'];
$s1=$_GET['size'];
$name1=$_GET['name'];

//连接数据库
$link=mysqli_connect("localhost",'root','','shop');
//设置编码
mysqli_set_charset($link,"utf8");
//SQL语句
$sql="UPDATE $u SET number = '$n' WHERE id='$x' AND name='$name1' AND size='$s1'";
//执行SQL语句
$result=mysqli_query($link,$sql);
//判断SQl语句执行是否成功
if($result){
    echo $a=10;     //执行成功
}else{
    echo $a=20;     //执行失败
}
//关闭数据库连接
mysqli_close($link);
?>